1. Field of the Invention
The present invention relates to a video CD reproduction controlling device and its controlling method for controlling reproduction of image data compressed and encoded by the MPEG-1 system recorded on a video CD.
2. Description of the Related Art
A video CD is capable of reproducing images and sounds for 74 minutes at the maximum, with compressed image data and sound data recorded in a time divided way on a CD-ROM format disk. Sounds and images including moving images and still images are recorded on a video CD in an efficient compress-encoding system by the MPEG-1 standard (hereinafter, referred to as the MPEG-1 system) regulated as the Advice ISO/IEC-11172-2 in 1993 by an expert group on ISO and CCITT (ISO/IEC, JTC1/SC2/WG8 (Moving Picture Expert Group: MPEG). The images and the sounds recorded on a video CD are reproduced by use of a video CD player with an MPEG video decoder and an MPEG audio decoder for respectively decoding MPEG-1 compression image data and MPEG-1 compression sound data mounted thereon.
FIG. 4 shows a schematic view of a construction of a disk for a video CD. With reference to FIG. 4, in the disk for the video CD, the data can be recorded on a lead-in L at the most inner portion, on a first track (T1), second track (T2), and third track (T3), successively to the maximum track 99. The lead-in L is the same as the lead-in provided in a musical CD (compact disc), where the information on each starting position for every track and the other necessary control information is recorded as the TOC information. The first track (T1) is a video CD data track with various disk information recorded therein. Further, the reproduction information T11 indicating the reproducing procedure of a disk and the image data T12 including moving images and still images can be recorded on the first track (T1). The second track (T2) and the later are MPEG-AV tracks respectively with one moving image recorded thereon. The MPEG data obtained by the time division and multiplexing of the compression image data and the compression sound data is recorded on these tracks.
A reproducing method of images and sounds recorded on a video CD includes a method for reproducing them in an interactive manner according to the reproduction information T11 recorded on the first track (T1) (referred to as reproduction with the playback control (PBC)-on) and a method for reproducing the second track (T2) and the later successively (referred to as reproduction with the PBC-off) regardless of the reproduction information T11.
FIG. 5 shows the constitution of the conventional video CD reproduction controlling device. The conventional video CD reproduction controlling device shown in FIG. 5 comprises a CD drive 51 for reading out the data recorded on a video CD, a CD-ROM decoder 52 for decoding the data read out through the CD drive 51 so to supply the reproduction data, an MPEG decoder 53 for decoding the MPEG data to supply image signals and sound signals when the reproduction data supplied from the CD-ROM decoder 52 is MPEG data, and a controller 54 for controlling the CD drive 51, the CD-ROM decoder 52, and the MPEG decoder 53.
The operation of the conventional video CD reproduction control in the case of PBC-off reproduction will be described with reference to the flow charts of FIGS. 4, 5, and 6. At the time of starting reproduction, if the PBC is set as off (Step 601), the controller 54 sends the CD drive 51 a seek request for the head of the second track (T2) that is the reproduction starting track (Step 602), in order to reproduce the images and sounds recorded on a disk set in the CD drive 51, and the data is read out and reproduced from the second track (T2) (Step 603). Namely, in case of the PBC-off reproduction, even if the image data T12 is recorded on the first track (T1), the same image data will be never reproduced, because the moving images recorded on the second track (T2) and the later are reproduced. The image data T12 recorded on the first track (T1) is to be reproduced only in case of the PBC-on reproduction.
Therefore, when a user wants to reproduce the images recorded on the first track (T1), he or she must select the PBC-on reproduction to perform the reproduction control of the video CD since it is impossible to reproduce the relevant images in the PBC-off reproduction.
There exists a video CD on which all the moving image data is recorded on the first track (T1) and no moving image data is recorded on the second track (T2) and the later. Although it is not against the video CD standards, such a video CD is incapable of reproducing the moving images completely when the PBC-off is selected.